The present invention relates to remote computer displays. In particular, this invention relates to a remote computer display which takes graphics primitives sent over a wireless link and converts the primitives into a graphics display.
The size of the built in video display for a portable computing device (PCD) is generally limited to the dimensions of the devices"" enclosure. Portable computing users accept smaller video displays in order to be mobile. Once back in the office or home environment however, small video display dimensions are a product liability.
Because PCD""s are reaching sufficient capabilities in computing speed, mass storage, and keyboard ergonomics, users are beginning to consider using a single computing device, their PCD. One important consideration in the decision to switch from using a non-PCD in the workplace, and a PCD for travel and home use are the dimensions of the video display.
Two techniques are generally used to connect a video display with larger dimensions to a PCD: a direct cabled connection to a video display device, or a xe2x80x9cdocking stationxe2x80x9d with its own video display device. A direct cabled connection requires that the PCD contain the interface hardware required to properly drive the video display. A docking station requires that the PCD contain the interface hardware required to properly connect to the docking station. This also implies that the number of different kinds of docking stations that may realistically be supported is limited to the amount of hardware support supplied in the PCD.
An alternative to a direct cabled connection or docking station is to allow the PCD to communicate over a wireless (this includes both radio frequency and optical such as infra-red light) data link to a remote display controller that supports a number of different video display devices. The advantage is that standard data link hardware and software protocols would already be built into the PCD to enable it to communicate with other data link compatible devices"". This eliminates the need for the video display driver hardware or docking station hardware to be built into the PCD.
To accomplish the task of drawing the images on the remote video display it is necessary to transfer the image, that the software in PCD is building, across the data link to the remote display controller. However, the data rate required to drive the video display device is quite high. For example to display a frame of video on a monitor having 1280 by 1024 pixels and 256 pixel colors, the PCD needs to transfer 335,544,320 bits of information to the remote display per frame displayed. The costs for such a high data rate link may be prohibitive given the price sensitivity of consumers.
Therefore what is needed in the industry is a means to reduce the bandwidth required to transfer display information to a remote computer display by a wireless data link.
The present invention provides a wireless remote computer display that minimizes the required data link bandwidth by sending graphics primitives over the data link. The number of primitive drawing instructions required to generate a video image are significantly less than required to directly transferring the video image as a bit stream. A wireless data link would transport the primitive drawing instructions from the PCD to the remote display controller. Hardware in the remote display controller interprets the primitive drawing instructions and generates the video image on the remote computer display.
In a PCD, applications make requests to the operating system to manipulate the video display. The operating system passes the requests to an appropriate software video driver. The video driver interprets the requests and generates changes to the appropriate pixels on the video display. In the present invention, the software video driver in the PCD is used to send the primitive drawing instructions to a protocol module responsible for communicating across the wireless data link to the remote display controller. The remote video controller contains a software and/or hardware driver that interprets the primitive drawing instructions and generates the image on the video display.
The advantages of the present invention are: a PC can be serviced by any remote display controller using a standard wireless data link protocol, the PCD vendor gets a larger video display capability by adding a software driver, the user has one less cable to plug in, and the hardware in the remote display controller may be optimized to perform the image generation faster than is possible by the PCD.